1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, to a semiconductor device having a dynamically reconfigurable circuit configuration.
2. Description of the Related Art
A conventional semiconductor device such as an LSI is generally fabricated to be able to execute predetermined processing meeting required specifications, by determining, in a designing step, the arrangement of AND gates, OR gates, and the like and their interconnections so as to execute the predetermined processing. That is, to realize a desired function in a conventional semiconductor device, this semiconductor device realizing the function is fabricated by designing the circuit configuration (logic configuration) for each gate (on each gate level).
Unfortunately, the circuit configuration of the above semiconductor device is fixed in the designing step. Therefore, to execute processing meeting different required specifications by changing specifications and the like, design and fabrication must be entirely performed each time. This requires much labor and time, and the development cost is also high.
One method solving this problem is a reconfigurable semiconductor device called a reconfigurable LSI capable of changing processing to be executed by reconfiguring the logic even after fabrication. This reconfigurable semiconductor device has a plurality of arithmetic units each receiving a control signal (configuration information) from a CPU, and capable of changing its function. This arithmetic unit is formed by appropriately combining a shifter, ALU (Arithmetic and Logic Unit), selector, and the like, and can change processing to be executed by receiving the configuration information from the CPU, and reconfiguring the logic accordingly.
Also, as address control concerning memories, a technique which holds a memory address in a memory (register) is disclosed (e.g., Patent Document 1).
[Patent Document 1]
Japanese Patent Application Laid-open No. Hei 6-309223.